Turbine with brake and thermostatic speed control



United States Patent [72] Inventor Eugene R. Braun Royal Oak, Michigan[21] Appl. No. 753,625 [22] Filed Aug. 19,1968 [45] Patented Oct.13,1970 [73] Assignee Eaton Yale 8L Towne Inc.

Cleveland, Ohio a corporation of Ohio [54] TURBINE WITH BRAKE ANDTHERMOSTATIC SPEED CONTROL 7 Claims, 1 Drawing Fig.

[52] US. Cl 192/3, 192/.094, 192/13: 74/339: 188/901137/51: 60/3916.60/3928 [51] Int. Cl Fl6d 67/00 [50] Field ofSearch l92/3,4(B),.058,.O94;7-1/339 [56] References Cited UNITED STATES PATENTS 3,03 l 0504/1962 Williams .1 192/3 Primary E.raminerBenjamin W. Wyche, lllAttorney-Woodhams, Blanchard and Flynn ABSTRACT: In an engine havingspeed controlling means and an output shaft connected in associationwith load means an energy absorbing device is connected to the outputshaft for regulating the output speed thereof and fluid circuit meansconnected to the energy absorbing device for supplying and circulatingfluid thereto. Temperature responsive means are connected in associationwith the fluid circuit means and responsive to the temperature of saidfluid to issue a signal at a predetermined temperature of the fluid.Transformation means are .also provided and are connected for actuationby said signal and further connected to the speed controlling means ofthe engine for controlling the rate of rotation of the output shaft ofthe engines.

Pafnted Oct. 13, 1970 INVENTOR. Z/Gf/VF E BEAU/V TURBINE WITH BRAKE ANDTHERMOSTATIC SPEED CONTROL FIELD OF THE INVENTION This invention relatesto an assembly of a prime mover, such as a gas turbine, having atendency toward excessive speed when the load is removed and a geartransmission utilizing spur gears and, more particularly, relates to anenergy absorbing device connected in association with a prime mover andhaving means responsive to the temperature of an energy absorbing anddissipating liquid circulating through the energy absorbing device forgoverning the fuel input to the engine.

BACKGROUND OF THE INVENTION In the development of gas turbines forautomotive use, a variety of problems have been encountered of which oneof the most troublesome has been the association of the turbine witheffective transmission means for providing suitable speed ratios betweenthe turbine output and the drive wheels of the vehicle. While theso-called two shaft, or free, turbine has more nearly approached theideal torque curve for vehicular applications than the earlier knownsingle shaft turbine, it is still desirable for the usual, andwell-understood reasons to interpose a ratio changing device between theturbine output and the drive wheels of the vehicle. Some efforts in thisdirection have taken the form of torque converters, which, however, arenot particularly efficient when used with a single shaft turbine and areeven less efficient when used with a free turbine. This efficiency canbe appreciably improved if the turbine is used with the transmission ofthe spur gear type but this introduces the problem of turbine runawaywhen the transmission is in neutral. This problem is serious enough initself but it also complicates the synchronizing of the ratio gearsduring a shifting operation. Hence, it has in the past been thought thata transmission of the spur gear type, to be effective with a gasturbine, would either have to be capable of being shifted practicallyinstantaneously or that means would have to be provided by which thetransmission would impose a constant load on the turbine during itsshifting procedure. The first of these possibilities is not feasible,particularly in a transmission of substantial weight, such as thetransmissions used in a highway bus or in a truck, due to the weight ofthe parts and the time consequently required to overcome their inertiain connection with a shifting operation. The second of thesepossibilities is effective and is receiving serious attention. Itsometimes takes the form of a friction brake mechanism (as in U.S. Pat.No. Application Ser. No. 669,046, assigned to the same assignee as thepresent invention) or a fluid retarder attached to the output shaft ofthe turbine. Both of these systems may, and often do, utilize a liquidas an energy absorbing and dissipating medium. These arrangements,however, while effective sometimes permit the power output of the engineto continue at a high level even when the load has been removed from theoutput shaft. This will often occur during a shift since driverscommonly hold the accelerator pedal unchanged during a shift. If thisoccurs, high temperatures are developed in the energy absorbing mediumand such high operating temperatures not only impair the capacity of themedium to absorb further energy (heat) but said high temperatures canand often do damage the various operating components within the liquidcircuit.

Furthermore, since there is no load being driven by the gas turbineengine during this time but a high level of power is being developed,fuel is wasted.

Accordingly, apparatus is highly desirable which will both protect aturbine engine from overspeeding when the load is removed and protect itfrom overheating of the retarder system by automatically reducing thefuel supply to the engine if and as needed and if the operator does not.Therefore, the objects of this invention include:

I. To provide a temperature responsive gas turbine engine control devicewhich is responsive to the temperature of energy absorbing means forcontrolling the speed of rotation of the output shaft of the gas turbineengine.

2. To provide a temperature responsive gas turbine engine control devicewhich is operable independent of the operator. '1

. To provide a temperature responsive gas turbine engine control device,as aforesaid, which protects the engine from overspeeding and protectsthe output shaft retarding mechanism from'damage due to overheating.

4. To provide a temperature responsive gas turbine engine controldevice, as aforesaid, wherein the fuel consumption of the gas turbineengine is controlled during the time that the speed of rotation of theoutput shaft is being checked.

. To provide a temperature responsive gas turbine engine control device,as aforesaid, which is reliable and operable at a minimum ofmaintenance.

6. To provide a temperature responsive gas turbine engine controldevice, as aforesaid, which is inexpensive to as semble utilizingreadily available components.

Other objects and purposes of this invention will be apparent to personsacquainted with apparatus of this general type upon reading thefollowing specification and inspecting the accompanying drawing whichschematically illustrates the temperature responsive gas turbine enginecontrol device.

Certain terminology will be used in the following description forconvenience in reference only and will not be limiting. The words up",down", right" and left" will designate directions in the drawing towhich reference is made. The words front" and rear will refer todirections to the left and to the right, respectively, of the deviceillustrated in the drawing. The words in" and out" will refer todirections toward and away from, respectively, the geometric center ofthe device and designated parts thereof. Said terminology will includethe words above specifically mentioned, derivatives thereof and words ofsimilar import.

LII

SUMMARY OF THE INVENTION The objects and purposes of the invention aremet by providing a temperature responsive device arranged in associationwith engine connected energy absorbing means and responsive to thetemperature of said energy absorbing means. Said device will issue asignal at a predetermined temperature in said energy absorbing means foractuation of transformation apparatus which is connected to speedcontrolling apparatus on an engine, whereby to control the rate ofrotation of the output shaft thereof.

DETAILED DESCRIPTION Referring now to the drawings for illustration of aspecific embodiment of the invention, there is shown a free turbinetypegas turbine engine 11 of the type for use in land vehicles such astrucks, automobiles and the like. The engine 11 comprises compressorapparatus 12, combustion apparatus 13 and a compressor turbine 14. Thecombustion apparatus comprises a fuel pump 15 which delivers fuel to avalve 16 controllable by a lever arm 17. The fuel is then supplied to aline 18, manifold 19 and nozzles of which one appears at 21.

The turbine 14 includes a rotor 22 which is connected by a shaft 23 tothe rotor 24 of the compressor apparatus 12. The compressor apparatus12, combustion apparatus 13 and turbine l4 constitute a gas generator26. The rotors 22 and 24 and the shaft 23 constitute a gas generatorrotor 27, hereinafter referred to as the rotor. The motive fluid ordriving gas discharged from the gas generator 26 flows through a powerturbine 28 which drives a power output shaft 29. The power output shaftis coupled through an appropriate coupling device 31 to the input shaft32 of a fiuid retarder mechanism 33, such as that shown in detail inU.S. Pat. No. 3,291,268, wherein a liquid is used as the energyabsorbing medium. The gas exhausted from the power turbine is dischargedthrough a duct 34.

A gear 36 is mounted on, or otherwise coupled to, the output shaft 29and is rotatable therewith. A gear 37 is supported on a shaft 38, isrotatable therewith and is in driving engagement with the gear 36. Aclutch 40 is interposed on the shaft 38 between the gear 37 and astandard-type, spur gear, transmission 39. The transmission has anoutput shaft 41 in driving engagement with a load, such as the wheels 42ofa vehicle.

The retarder mechanism 33 used in this embodiment may be, with propercontrols, the same mechanism as that utilized also to prevent downhillvehicle runaway (as in US. Pat. No. 3,291,268) or it may be providedsolely to control the turbine. However, as illustrated and describedherein it is assumed to be solely for controlling the turbine and, assuch, is shown connected to the turbine output shaft and is assumed tobe of horsepower capacity only to prevent turbine runaway. Said retardermechanism 33 has a fluid circuit 46 connected in association therewith.More particularly, the retarder mechanism 33 comprises an input member47 and an output member 48. In this particular embodiment, the outputmember 48 is fixed to a stationary frame 49. The input member 47 isspaced slightly axially from the output member 48 to define a pressurecreating zone 51 and a fluid discharge gap 52 therebetween.

The pressure creating zone 51 is defined by a pair of oppositely facingannular troughs 53 and 54 of semicircular cross section. Each trough 53and 54 has a plurality of circumferentially spaced blades 56 and 57,respectively, oriented as disclosed in said U.S. Pat. No. 3,29 l ,268.

The fluid, here liquid, circuitry 46 comprises a liquid reservoir 6].having a conduit 62 interconnecting the reservoir 61 with the input of apressure creating device such as a pump 63. A conduit 64 interconnectsthe output of the pump 63 with the input of a heat exchanger 66.

A conduit 67 interconnects the output of the heat exchanger 66 with theinput of a control valve 68. The heat exchanger 66 must be selectivelymatched to the maximum energy absorption of the retarder which is inturn matched to the engine 11 so that the horsepower capacity thereof isless than the horsepower output of the engine 11 at some selected safespeed and load condition. For example, where a liquid retarder is used,the selected condition may be normal operating speed at the full load ofwhich the retarder is capable. Thus, the temperature of the liquidwithin the circuit 46 will rise whenever the turbine speed exceeds suchsafe condition which it will tend to do if, for example, the operatorundertakes a shift at full throttle.

The control valve 68 is controllable by any convenient means such as amanually operated pedal 70. It is to be recognized, of course, that thepedal 70 can also operate the clutch 40 (indicated by the broken line74) so that the operativeness of the retarder mechanism 33 will besynchronized with the disengagement of the clutch 40 and the removal ofthe load from the output shaft 29 of the engine 11 independent of theoperator. A conduit 69 interconnects the output of the control valve 68with the pressure creating zone 51 in the retarder mechanism 33. Areturn conduit 71 interconnects the bypass port on the control valve 68with the reservoir 61. A conduit 72 interconnects a fluid accumulationchamber 73 surrounding the discharge gap 52 with the reservoir 61.

In this particular embodiment, a temperature sensing element 76 islocated in the conduit 67 for sensing and monitoring the temperature ofthe fluid flowing therethrough. While for illustrative purposes theelement 76 has been shown in the conduit 67, and such is one preferredlocation, it will be recognized that it can be located anywhere where itwill be sensitive to the energy absorbed by the brake. This, forexample, includes also the temperature of the fluid anywhere in theretarder system, including within the retarder mechanism 33 itself orwithin or on any conduit or liquid containing chamber. A temperatureresponsive element 77 is connected in association with the temperaturesensing element 76 and is responsive to the temperature detectedthereby. A lever arm 78 is operable in response to the input to thetemperature responsive element 77. In this particular embodiment, thelever arm 78 is pivotable forwardly and rearwardly about the pivot axis79 in response to the temperature detected by the temperature sensingelement 76.

A linkage system 81 interconnects the ends of the lever arms 17 and 78and includes a link 82 which is pivotable about a pair of parallel pivotaxes 83 and 84. A link arm 86 interconnects the link arm 82 at the pivotaxis 84 with the free end of the lever arm 78. A link arm 87interconnects the link arm 82 at the pivot axis 88 with the free end ofthe lever arm 17 on the valve 16.

An accelerator pedal 89 is pivotable about a pivot axis 91 and isconnected through a link arm 92 to the link arm 82 at the pivot axis 83.The link arm 92 is connected to the accelerator pedal 89 at the pivotaxis 93 so that movement of the pedal 89 will cause a movement of lever17 on the valve 16.

It is to be recognized that other types of feedback apparatus can beutilized in place of the linkage system 81 to transfer the signalindicating an increased temperature in the liquid circuitry to the fuelcontrol apparatus 16 and 17.

OPERATION The operation of the device embodying the invention has beenindicated above but will be described in detail hereinbelow to insure afull understanding ofthe invention.

When the output shaft 29 of the gas turbine engine 11 is connected tothe drive wheels 42 of a vehicle through the clutch 40 and transmission39, the liquid retarder mechanism 33 is in a conventional mannerrendered inoperative by control valve 68. Thus, there will be no drag onthe output shaft 29 of the engine 11 during a driving or cruisingcondition.

However, during a shift of the transmission 39 from one gear ratiothrough neutral to another gear ratio, a movement of the pedal operatesthe clutch 40 to disconnect, though only momentarily, the transmission39 from the gear 37 and shaft 38 so that the output shaft 29 would tendto accelerate at a dangerous rate. However, the operation of the pedal70 will simultaneously render the control valve 68 operative to permit aflow of liquid therethrough to the pressure creating zone 51 in theretarding mechanism 33. During the gear shifting operation, the inputmember 47 is rotating at a normal turbine rotational speed, namely30,000 rpm, heat is generated in the fluid which must be dissipated bythe heat exchanger 66. If the operator reduces the fuel supply toessentially no load conditions, then the power output of the turbine tobe absorbed by the retarder and dissipated by the heat exchanger will bewithin the capacity of the heat exchanger and the temperature of theretarder liquid will not rise. However, if the operator maintains thefuel supply at full power during the shift, then however, even thoughthe liquid is driven through the heat exchanger 66, the temperature ofthe liquid will increase since the horsepoweroutput of the engine anddirected by the retarding mechanism into the retarder liquid is greaterthan the horsepower capacity of the heat exchanger. As a result, thetemperature of the retarder liquid will rise and the temperature sensingelement 76 will sense the increased temperature. This will cause thetemperature responsive element to move the lever arm 78counterclockwise.

If it is still assumed that the operator maintains a constant pressureon the accelerator pedal 89, a counterclockwise movement of the leverarm 78 will cause a clockwise movement of the link arm 82 about thepivot axis 83. This in turn will cause a clockwise movement of the leverarm 17 on the control valve 16 to decrease the quantity of fuelintroduced into the combustion apparatus 13 through the nozzles 21.Accordingly, the horsepower output of the engine 11 is decreasedindependent of the operator's control of the accelerator pedal 89 to alevel within the horsepower capacity of the heat exchanger and within asafe value for the other associated equipment.

The invention has for simplicity of illustration been shown with theengine connected directly to the fluid coupling and this arrangement isdesirable for a high speed (as 30,000 rpm.) engine in order to enablethe coupling to be of very small diameter. However, wherever it isdesirable to have the coupling run at any speed, faster or slower, thanthat of the engine, it will of course be possible to gear same up ordown as necessary, or otherwise provide in any conventional manner for asuitable ratio relationship between the speed of the engine and that ofthe coupling. Particularly, it will be recognized that where, if at all,the lineal speed of the coupling blades creates a cavitation problem,the coupling may be geared down to the extent necessary withoutdeparture from the concepts of the invention.

Similarly the two sides of the fluid coupling are for simplicity shownas mounted directly on the engine shafts. it will be obvious in view ofthe foregoing that either or both of them may be indirectly connected tothe engine shafts in any manner to maintain a selected speed ratiobetween the respective sides of the coupling and the shafts of theengine respectively connected therewith. For example, the left side ofthe coupling may be driven from the shaft 38.

lclaim:

1. in combination with an engine having operator controlled powercontrolling means and an output shaft connected in association with loadmeans, a speed limiting mechanism connected to the output shaft forabsorbing energy therefrom, comprising:

energy absorbing monitoring means connected in association with saidspeed limiting means responsive to the energy absorbed by said speedlimiting means and capable of issuing a response at a predeterminedlevel of absorbed energy; and

transformation means connected for actuation by said energy absorbingmonitoring means and further connected to said power controlling meansof the engine for controlling the power output of said engine, saidenergy absorbing monitoring means continuously monitoring the energyabsorbed by said speed limiting mechanism over a prolonged period ofoperation of said engine and responding to an exceeding of apredetermined value of absorbed energy in said speed limiting mechanismto limit the power output of said engine independent of the operatorscontrol of the power controlling means and after said power output ofsaid engine has been limited and the response of said energy absorbingmonitoring means indicates that said absorbed energy is reduced belowsaid predetermined value, said transformation means will respond to saidenergy absorbing monitoring means to return said power controlling meansto the control of the operator so that the power output of the enginecan be set at a desired level providing said desired level is below saidpredetermined value of energy absorbed by said speed limiting mechanism.

2. in combination with an engine having operator controlled speedcontrolling means and an output shaft connected in association with loadmeans, a fluid retarder mechanism connected to the output shaft forregulating the output speed thereof, and having fluid circuit meansconnected to said retarder for supplying the circulating fluid thereto,comprising:

temperature monitoring means connected in association with said fluidcircuit means of the retarder for monitoring the temperature of thefluid in said circuit means and capable of issuing a response at apredetermined temperature of said liquid; and

transformation means connected for actuation by said temperaturemonitoring means and further connected to said speed controlling meansof the engine for controlling the rate of rotation of the output shaftof said engine, said temperature monitoring means continuouslymonitoring the temperature of the fluid in said circuit means, whichtemperature is increased and decreased as a function of the energyabsorbed by said fluid retarder mechanism, over a prolonged period ofoperation of said engine and responding to an exceeding of apredetermined temperature value of the fluid in said circuit means tolimit the power output of said engine independent of the operatorscontrol of the speed controlling means and after said power output ofsaid engine has been limited and the response of said temperaturemonitoring means indicates that said temperature of said fluid in saidcircuit means is reduced below said predetermined value, saidtransformation means will respond to said temperature monitoring meansto return said speed controlling means to the control of the operator sothat the power output ofthe engine can be set at a desired levelproviding said desired level produces a temperature in said fluid whichis below said predetermined temperature value of the fluid in saidcircuit means.

3. In combination with an engine having operator controlled powercontrolling means and an output shaft connected in association with loadmeans, a speed limiting device having fluid means for absorbing energytherefrom comprising:

energy absorbing monitoring means connected for monitoring the energyabsorbed by said fluid means and capable of issuing a response at apredetermined level of absorbed energy; and

transformation means responsive to said energy absorbing monitoringmeans and further connected to said power controlling means of theengine for controlling the power output of said engine, said energyabsorbing monitoring means continuously monitoring the energy absorbedby said speed limiting device over a prolonged period of operation ofsaid engine and responding to an exceeding of a predetermined value ofabsorbed energy in said speed limiting device to limit the power of saidengine independent of the operators control of the power con trollingmeans and after said power output of said engine has been limited andthe response of said monitoring means indicates that said absorbedenergy is reduced below said predetermined value, said transformationmeans will respond to said energy absorbing monitoring means to returnsaid power controlling means to the control of the operator so that thepower output of the engine can be set at a desired level providing saiddesired level produces an energy level which is below said predeterminedvalue of energy absorbed by said speed limiting device.

4. In combination with an engine having operator controlled powercontrolling means and an output shaft connected in association with loadmeans, a speed limiting device having liquid flowing therethrough forabsorbing energy therefrom comprising:

temperature monitoring means for monitoring the temperature of theliquid indicative of the energy absorbed by said liquid and issuing aresponse at a predetermined value of absorbed energy as measured by thetemperature of said liquid; and

transformation means connected for actuation by said temperaturemonitoring means and further connected to said power controlling meansof the engine for controlling the power output of said engine, saidtemperature monitoring means continuously monitoring the temperature ofthe liquid flowing through said speed limiting device over a prolongedperiod of operation of said engine and responding to an exceeding ofsaid predetermined temperature value of the liquid to limit the poweroutput of said engine independent of the operators control of the powercontrolling means and after said power output of said engine has beenlimited and the response of said temperature monitoring means indicatesthat said absorbed energy is reduced below said predetermined value,said transformation means will respond to said temperature monitoringmeans to return said power controlling means to the control of theoperator so that the power output of the engine can be set at a desiredlevel providing said desired level produces a liquid temperature whichis below said predetermined temperature value.

5. The device defined in claim 1, wherein the speed controlling meanscomprises control means for the fuel input to said engine.

6. The device defined in claim 1, wherein said temperature monitoringmeans monitors the temperature of a liquid in said circuit means.

liquid brake means operatively connected to said prime mover forpreventing excessive speed of said prime mover when said transmission isin said neutral position; temperature monitoring means connected inassociation with said liquid brake means for monitoring the temperatureof the liquid flowing therethrough, said temperature monitoring meanscapable of issuing a response at a predetermined temperature of saidliquid; and transformation means connected for actuation by saidtemperature monitoring means and further connected in association withsaid prime mover for controlling the rate of rotation of the outputshaft of said prime mover, said temperature monitoring meanscontinuously monitoring the temperature of the liquid flowing throughsaid liquid brake means over a prolonged period of operation of saidprime mover and responding to an exceeding of a predeterminedtemperature of said liquid to limit the power output of said prime moverindependent of the operator's control of the power controlling means andafter said power output of said prime mover has'been limited and theresponse of said temperature monitoring means indicates that saidtemperature is reduced below said predetermined temperature of saidliquid, said transformation means will respond to said temperaturemonitoring means to return said power controlling means to the controlof the operator so that the power output of the prime mover can be setat a desired level providing said desired level operates said liquidbrake means so as to generate a temperature in said liquid which isbelow said predetermined temperature of said liquid.

